In conventional wireless communications, a radio access network will have hardware configured to exchange wireless signals with mobile terminal devices. The radio access network generally covers a geographic area that is subdivided into smaller regions served by central hardware components. The basic unit of subdivision is the network cell, which generally covers an area over which a base station can reliably receive signals from, and transmit signals to, the mobile terminal devices within the network cell. Although various conditions can change a cell size or base station signal strength, such as transmit power, interference, signal reflections or scattering off of physical structures or landscape (buildings or mountains, for instance), the network cell will always be the unit of subdivision employed in wireless networks.
Wireless transmission hardware typically comprises a transmitter coupled with a signal modulator and signal processor, as well as a receiver coupled with a signal demodulator and receive processor. Radio frequency bandwidth allocated to a network cell, processor capacity, power, memory, and the like are all resources employed to facilitate the wireless signal exchange. Like most resources, a physical limit on the number of terminals, or the amount of traffic that can be handled by a network cell at a given time is determined by those resources. The relationship between available resources and available cell capacity is direct; that is, as fewer wireless resources are available in serving terminals capacity of the cell decreases. Likewise, as more resources are available, capacity increases.
One design constraint involved in wireless networking is load balancing. Although a typical network cell size can be determined by the performances of the base station, the number of terminals within the cell is completely independent of that range. A particular problem arises when the number of terminals attempting to obtain service from a cell is far greater than the physical resources of the base station.
One mechanism to serve high population densities (with large numbers of access terminals) is to increase the amount of hardware resources within a given cell. In some instances, a wireless tower might have several wireless transceivers, each with separate hardware resources. In some cases, the wireless transceivers can be aimed in a particular direction, or sector, of the cell, enabling multiple wireless transceivers to serve respective sectors of the cell. This can multiply the signal resources (each sector having substantially all signal bandwidth utilized by the cell) as well as hardware resources (multiple transceivers having multiple processors, memory, etc.) available to serve higher terminal densities within the cell.
In geographic regions where high terminal density is relatively constant, adding additional hardware to cells of those regions can be an efficient way to multiply wireless network resources. Where population density is not constant, and particularly where it can change drastically, however, simply adding hardware is not an efficient mechanism for serving network traffic. Unfortunately, this is a relatively common occurrence. Office buildings, for instance, generally have many times the human population density (and terminal density) during business hours than outside them. But even more lopsided terminal density can exist. Stadiums, for instance, can cause dozens of thousands of people to aggregate in a relatively small area (generally smaller than a network cell), with dozens of thousands of terminals. Because these events last only for a few hours, and on sporadic occasions, such events cause a huge spike in terminal density that is not otherwise observed in a given network cell. The circumstances can make network resource planning very difficult.
Wireless hardware installations are more or less permanent (relative to changes in terminal population density). Accordingly, it may be cost prohibitive to install sufficient wireless transceivers to accommodate peak population density, for widely divergent terminal population densities. On the other hand, lesser hardware installations can become quickly overloaded when terminal density exceeds resource capacity. A resource overload condition can cause unpredictable wireless service, including dropped calls, service outage, or even large scale call failures within those regions. Because consumer satisfaction is an essential aspect in the competitive field of wireless communication services, existing research and development is directed toward avoiding these problems in general, and particularly for non-constant population densities.
The above-described deficiencies of today's wireless communications systems are merely intended to provide an overview of some of the problems of conventional systems, and are not intended to be exhaustive. Other problems with the state of the art and corresponding benefits of one or more of the various non-limiting embodiments may become further apparent upon review of the following detailed description.